On ZendCasts.com there's a new screencast posted introducing you to the Zend Framework feature called "action helpers".

A look at how Action Helpers can help you build controller-level-functionality without duplicating code.

Action helpers allow you to, at runtime, push code into the processing of a controller to make changing the processing of your controllers simpler than changing its actual code. You can also find a good guide on getting the helpers working in the Zend Framework manual.